Alarm apparatus



OCLZZ, 1929. J MORRISON 1,732,276

ALARM APPARATUS Filed April 29. 1926 ml 22 4/ INVENTOR.

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rarss steam errnnn ros Application filed April 29,

My invention relates to burglar and [ire alarm apparatus, and a purposeof my invention is the provision of an apparatus which can beapplied toa building or the like to actuate an alarm when the surreptitiousopening of a door or window is effected or when a fire occurs in thebuilding;

It is also a purpose of my invention to provide an electrical burglarand fire alarm apparatus which normally utilizes the house or lightingcurrent and which is operable to prevent actuation of the alarm shouldthe lighting current for any reason becut off or fail,

yet maintaining the apparatus operable to,

sound the alarm inthe event of fire or bur- -lary.

A. further purpose of my invention is the provision of an apparatuswhich normally consumes a relatively small amount of the lightingcurrent to render it operative, and which utilizes local batteries onlyto actuate the alarm and to thus impose a relatively small drain on thebattery current.

I will describe only one form of combined burglary and fire alarmapparatus embody ing my invention, and will then point out the novelfeatures thereof in claims.

In the drawings Figure 1 is a view showing diagrammatiso cally one formof combined fire and burglar alarm apparatus embodying my invention,

with the parts thereof in normal position;

Figure 2 is a view similar to Figure 1, showing the parts of theapparatus in the positions when the alarm thereof is being actuatedFigure 3 is a detail view of one of the relays embodied in the apparatusshown in the preceding views, and disclosing the other position of itsarmature contacts. I Referring specifically to the drawings, myinvention in its present embodiment comprises a source of alternatingcurrent supply which may be the house or lighting current of a buildingand which is represented in Fig ure 1 as comprising conductors 15 and16. In this lighting circuit the primary winding 17 of a step-downtransformer is'interposed,

and connected in parallel with the primary winding is a windmg of arelay R having an 1926. Serial No. 165,544..

armature 18 to which is secured an insulation. '18, This insulation inits turn supports two conducting sections so that the sections areinsulated from each other as well as from the armature. One of thesesections carries there on a contact 19, and the other section carriesthereon a contact 20, and stationary contacts 21 and 22 are placed insuch a relation to the contacts 19 and 20 that, when the relay isenergized, the contact 19 engages the contact so 21, whilethe contact 20disengages the contact 22, as shown in Figs. 1 and 2. "With the relayde-energized the armature is moved to cause the contact 19 to disengagethe contact 21 and the contact 20 to engage the contact 22, e5 i asshown in Fig. 3.

The secondary winding 23 of the transformer is included in a controlcircuit having a conductor 24 capable of being readily cut, broken orfused and which is of such length as to be extended from door to door orwindow to window of a building and in such manner that .when the doorsor windows are opened the conductor will be disrupted, therebydisrupting the control circuit. By virtue of the fact that the conductor24 is fusible it is manifest that in the event of fire in the buildingthe control circuit will likewise be disrupted.

Also included in the control circuit is the so winding of a relay R"having two pairs of armature contacts 25 and 26 insulated from eachother and disengaging respectively two pairs of stationary contacts 27and 28 when the relay is energized, but movable to engage 35 suchcontacts when the relay is de-energized. The contacts 25 and 27constitute the terminals of an alarm circuit including an alarm, whichin the present instance is a motor-operated horn.29, and a battery 30for supplying current to and actuating the motor of the horn so that thelatter will be sounded. The horn motor is designed to actuate acentrifuge 31 for opening a normally closed switch 32 included in thecontrol circuit and functioning to prevent closing of the controlcircuit following an opening thereof through severin of the conductor24.

&his horn motor may be of any approved type and provided with the usualsoundproducing means.

For instance, the horn motor may be used in connection with a siren ofthe type disclosed in Letters Patent of the United States, No.1,205,371, granted-Nov. 21, 1916'. The siren in this patent comprisesthe combination With a casing of a rotor. It being assumed that such acombination or an equivalent combination of sound-producing means isused in connection with the horn motor 29, the rotor is indicated inFigs. 1 and 2 by' the letter a, and the motor shaft, on which the rotora-is mounted, is indicated in'the same figures by the, letter 6, and itis understood that the centrifuge 31 is suitably connected with the endof the motor shaft 6, so that, when the horn motor causes the centrifugeto be actuated, the sound-producingmeans are operated in order to givean audible alarm simultaneously with the opening of the switch 32.

To control the alarm circuit independently of the relay R, I provide asecond relay R the winding of which is interposed in a circuit includinga battery'33 and the contacts 26, 28, 20 and 22, so that, when theseveral contacts areclosed, current will be supplied from the battery 33to the winding of the relay R to energize the latter, it beingparticularly noted that the relay R is a direct current relay, while therelays R and R are alternating current relays.

The relay R provides additionalmeans for controlling the alarm circuit,its armature 34 being adapted to bridge a pair of contacts 35 when therelay is de-energized, but when the relay is energized the armature 1s'moved to disengage the contacts. v

The operation of the apparatus is as follows:

l/Vith current constantly flowing in the lighting circuit the relay R isenergized to cause its contacts to occupy ,the position shown in Figure1, while current from the primary winding 17 is induced into thesecondary winding to energize the relay R and thus maintain the contacts27 and 28 open.

Should the conductor 24 be disrupted for any reason, the control circuitis "opened so as to de-energize the relay R, thereby closing thecontacts 25 and 27 and hence the alarm circuit to sound the horn 29.Current is then supplied to the alarm as follows: From positive side ofbattery 30 through wire 36, contacts'35 and armature 34, wire 37,contacts 25 and 27, Wire 38, horn motor 29 and wire-39 back to battery.Upon energization of the horn motor the centrifuge 31, after attaininga. certa-in speed, eflects the operation of the sounding means andcauses the switch 32 to open, so that, should one attempt to bridge thegap in the conductor 24, it will be ineffective to restore continuity ofthe control circuit. It will thus be seen that unless the alarm circuitis. disrupted the alarm will continue to sound. However, to permit thosewith proper authority to discontinue sounding of the horn the wire 39has interposed therein a switch- 40 which, when opened, will disrupt thealarm circuit.

Should the lighting circuit for any reason fail or-be intentionally cutoff, the relay R and the transformer will be de-energized, and withde-energization of the latter the relay R will likewise be de-energized,so that the armatures 18 and 25, respectively, of the two relays willmove to positions in which the contact 19 is open, the contact 20 closedand the contacts 27 and 28 closed. With both relays R and R de-energizedand the control circuit intact the direct current relay R is nowenergized through the following circuit to prevent sounding Frompositive side of battery 33 through Wire 41, contacts 22 and 20, wires42 and 43, con- From this operation it will be manifest that failure ofthe lighting current will be ineffective to actuate the alarm. However,

the apparatus is still operative to actuate the alarm should theconductor 24 be disrupted because of the fact that through itsdisruption the circuit from the relay R is broken,

thereby causing de-energization of the relay to close the contacts 35and thereby permit the battery 30 to supply current to the motor of thehorn.

Through opening of the contacts 19 and 21 with de-energization of therelay R the tie-energization of the relay R on account of the failure ofthe lighting current is prevented, so that therebythe operation of thehorn motor is assured.

I claim:

1. An alarm apparatus comprising an alarm, a circuit therefor, a controlcircuit having a conductor capable of being fused or severed, a relay inthe control circuit controlling the alarm circuit in such manner thatWhen the control circuit is disrupted the relay will be de-energized toclose the alarm circuit, a second relay having its contacts included inthe alarm circuit and being adapted to control the alarm circuit inconjunction with the first relay, the first relay being normallyenergized and the second relay normally de-energized, and means by whichthe second relay is energized to open the alarm circuit when the supplyof current to the control circuit fails.

. 2. An alarm apparatus comprising a source of alternating currentsupply having a circuit including a relay and the primary winding of astep-down transformer, a control circuit including the secondary of thetrans1 former, and a conductor capable of being fused or severed, arelay in the control circuit, an alarm, an alarm circuit controlled bythe second relay, a direct current relay having its contacts included inthe alarm circuit and being adapted to control the alarm circuit inconjunction with the second relay, the relay in the control circuitbeing normally energized, and the direct-current relay being normallyde-energized, a normally closed switch in the control circuit, meansoperable by the alarm to open said switch, and means operable by therelay in the control circuit so as to energize the direct current relayto open the alarm circuit when the source of alternating current failsand to effect de-energization of the direct current relay When saidconductor is disrupted.

JOHN A. MORRISON.

